Experience 5 (Source)

BerentD actually that's not quite how it works, after extensive testing I've determined how the difficulty of the missions is determined on starting planets (still not sure on advanced ones yet), everyone has a level that is determined by the skills they have, this level is the level of missions you can get solo, when in a group the level of missions you can get is the sum of the levels in the group divided by 10, so lets say ur level 20, if you group with an atst (level 125) you can get missions of difficulty (20+125)/2=72 (round down), but on the other hand if you group with a level 1 pet (a baby) you can get missions of difficulty (20+1)/2=10 (round down again), so grouped with 1 thing lower level than you actually gets you worse missions, I found the formula to be accurate with multiple pets too, I tested it with faction pets before the ch changes, at level 25 grouped with 3 commando pets (each level 29) the formula would indicate a mission level of (29+29+29+25)/2=56 which is exactly what I got.

I'd also like to note that before the pet changes it was very possible to get insanely high difficulty with multiple atsts solo, lets say ur level is 25 and you had 3 atsts: (25+125+125+125)/2=200 difficulty missions I have noticed though when in large groups that you don't always get missions as high difficulty as you should, there seems to be some sort of cap on difficulty but I can't narrow down how the cap is determined, because I can get missions of the same type and see some at one common difficulty cap, while others of the same mission type would be at another common difficulty cap, the only thing I can think of is maybe distance because it seemed to me the higher difficulty ones were further.